Use of lidocaine metabolism to test liver function during the long-term follow-up of liver transplant recipients.

BACKGROUND/AIMS: The aim of this study was to assess the usefulness of the monoethylglycinexylidide (MEGX) test to monitoring the long-term function of liver allografts.
METHODS: MEGX production was measured prospectively in 60 consecutive liver transplant recipients undergoing their annual review.
RESULTS: Median MEGX values in liver recipients (54 ng/mL; range 10-146) were lower than those found in healthy controls (78 ng/mL; range 44-118). MEGX values correlated negatively with alanine aminotransferase (ALT) activity (p = 0.004) and with the overall histological score (p = 0.01), and positively with sulfobromophthalein (BSP) and indocyanine green (ICG) clearances (p = 0.0002 and p = 0.002, respectively). A stepwise decline was observed with worsening liver fibrosis, from 71 +/- 5 microg/L in patients with no fibrosis to 27 +/- 9 microg/L in patients with bridging fibrosis (p = 0.002). BSP and ICG clearances correlated more closely than the MEGX test with the overall histological score (p = 0.001 and p = 0.001, respectively) and portal fibrosis (p = 0.002 and p = 0.001).
CONCLUSIONS: The measurement of MEGX formation is a simple and non-invasive method to monitor liver graft function. It may constitute a valuable tool for assessing the degree of fibrosis.